Registered APPARATUS AND METHOD FOR MAINTAINING CONSTANT EXTINCTION RATIO OF LASER DIODE

Inventors

Lee Jun Ki, Lee Jyung Chan, Kim Kwangjoon

Application No.

11635196 (2006.12.07)

Publication No.

20070133634 (2007.06.14)

Registration No.

7869478 (2011.01.11)

Country

UNITED STATES

Project Code

05MT1500, 40Gb/s EDTM Optical Transmission Technology, Ko Je Soo

Abstract

Provided are an apparatus and method for maintaining an constant extinction ratio of a laser diode (LD). The apparatus includes: an automatic power control circuit maintaining the constant optical power of the LD; a correlation deriver deriving correlations between a bias current of the LD and a modulation current to maintain the constant extinction ratio of the LD; and a modulation current control circuit controlling the modulation current to maintain constant the extinction ratio of the LD based on the correlations. The apparatus and method do not use a temperature sensor but derive a relationship between variances of a bias current of the LD and a modulation current according to temperature change, control the modulation current based on the relationship, and maintain the constant extinction ratio of the LD.